Conventionally, a technique of having a stereoscopic view of a medical image by using a three-dimensional (3D) monitor has been known. For example, a 3D monitor enabling to have a stereoscopic view from parallax images that are imaged from two view points by using a special device such as stereoscopic glasses has been in actual use. Moreover, for example, a 3D monitor enabling to have a stereoscopic view without glasses from multiple parallax images (for example, parallax images from two points, parallax images from nine points, and the like) by using a beam controller such as a lenticular lens has been in actual use. By displaying a medical image on such a 3D monitor, an observer can obtain information in a direction of depth, and can understand spatial positional relationship easily.